Chitosan-based active films were developed by incorporation of carvacrol (10 g/L), pomegranate peel extract (PPE, 10 g/L) and carvacrol + PPE (10 g/L of each) and their physical, antioxidant and antimicrobial properties were investigated. Incorporation of carvacrol and carvacrol + PPE into the films significantly decreased the water vapor permeability, tensile strength and percentage of elongation at break. Incorporation of carvacrol, PPE and carvacrol + PPE into the films decreased the transparency, but significantly increased the total phenol content and antioxidant activity. All the films, with the exception of PPE-incorporated film, exhibited antibacterial activity against Escherichia coli and Staphylococcus aureus. In addition, the antibacterial activity against Staphylococcus aureus of the film incorporated with carvacrol + PPE was moderately higher than that incorporated with carvacrol or PPE alone, suggesting a synergistic action between carvacrol and PPE.

The subject of present study was to evaluate the effect of chitosan coating combined with green tea extract (GTE) on the melanosis formation and quality of Pacific white shrimp (Litopenaeus vannamei) during 9 days of storage in ice. The melanosis formation was significantly inhibited and sensory quality was significantly improved in shrimp treated with chitosan coating, GTE and chitosan coating combined with GTE, compared with the control. The increase in the total bacteria amounts, pH and total volatile basic nitrogen were significantly inhibited in shrimp treated with chitosan coating, GTE and chitosan coating combined with GTE. The melanosis score and total volatile basic nitrogen of shrimp treated by chitosan coating combined with GTE was less than that treated by chitosan coating or GTE alone. These results suggested that chitosan coating combined with GTE could be used as an effective natural alternative to synthetic antimelanosic agents to inhibit post-mortem melanosis and improve the quality of shrimp during storage in ice.